EP1963812B1 - Method and device for analysing the imaging behaviour of an optical imaging element - Google Patents

Abstract

In a process to evaluate the optical characteristics of a lens system, two properties are defined using first and second lens systems. Selecting the second property, a selected zone is broken down into smaller zones and an image allocated to each smaller zone and the image point intensity measured. The series of images in an emulation stage is converted into a series of intermediate images that are finally converted into an emulation image. The second set of images is compared to images defined by the first system.

Description

The invention relates to a method for investigating the imaging behavior of a first imaging optical system, in which an object is imaged by a second imaging optical system in an image plane and light is detected spatially resolved in pixels in the image plane, wherein the first and second imaging optics differ in at least one imaging property, wherein for each pixel, values for the intensity are determined as a first property of the light and stored in pixels, and wherein a series of images are generated.

The invention also relates to a device for examining the imaging behavior of a first imaging optics. Such a device comprises a second imaging optics, by means of which an object is imaged into an image plane and which differs from the first imaging optics in at least one imaging property, a spatially resolving detector with pixels, with which light in the image plane is detected in the pixels, as well a memory module in which spatially resolved intensity values are stored as pixels in a first property of the light, the device generating a series of images. The invention relates to the problem that in the prior art dependencies on a second property of the light - which may be, for example, the color or polarization - in the emulation only incomplete, for example, can be considered summarily.

The emulation of the imaging properties of optical systems can lead to inaccuracies in the emulation. For example, some errors are particularly noticeable when emulating high-aperture imaging optics with low-aperture imaging optics. Heretofore, for example, polarizing elements such as polarizers or gratings have been substantially examined and evaluated for their integral effect. However, with the development of micro- or nanostructured optical devices, the determination of local optical properties is becoming more and more important for the further development and improvement of manufacturing processes and to ensure product quality. As an example of such optical components is here a diffractive optical element (DOE) mentioned, as for example in the in WO 03/001272 A3 described hybrid lens is used. The optical effect of this DOE arises on the webs, which are arranged concentrically around the optical axis. The distance between two webs is not constant, but varies depending on the radius. The object of this element is a dispersively imaging color compensation within the objective, wherein the optical quality of the objective results from the interaction between the refractive lenses and the DOE. In order not to be able to judge the optical properties of the DOE until final assembly of the objective, it is desirable to study the optical effect in detail in advance. This can be done independently of the objective, or else by introducing it into the beam path of an imaging optical system, for example an emulation imaging system as a second imaging optical unit for emulating the relevant objective, the first imaging optics. The introduction of the DOE usually requires an adaptation of the beam path, both imaging optics differ at least in it. In addition, the second imaging optics can also be designed such that it images the object relative to the objective magnified or reduced.

Another example of such devices are classic linear diffraction gratings. In the lattice used for example in telecommunications is increased with increasing number of line pairs per unit area of energy and thus the efficiency in the zeroth diffraction order. With increasing number of lines, i. smaller structure sizes, the grating increases the polarizing effect.

Also in photolithography scanners, where the trend towards ever higher numerical apertures and ever smaller mask structures, polarization effects play an increasingly important role. However, with the emulation imaging techniques and systems heretofore known in the art, such polarization effects can only be described incompletely, since the polarization effect is only summarily, i. integrated over the image area.

From the WO 03/76891 For example, a method and a device are known with which aberrations such as the aberrations of a first imaging optics-for example a projection objective for photolithography-can be measured. The imaging optics is introduced into a second optical system, which has inter alia a lighting device, a second imaging optics and a spatially resolving detector. In the beam path, both on the object side as well as on the image side simultaneously a grid is introduced. The grids point to each other adapted structures in the form of sublattices with line patterns. The object-side lattice is imaged onto the image-side lattice, so that the images of the lattices overlap on the detector and produce moire patterns. The grids are mounted rotatable and / or displaceable. The disturbances can be determined by taking and evaluating series of images with different positions of the grids.

The object of the present invention is therefore to further develop a method and a device of the type described at the outset such that optical properties and factors which influence the imaging behavior of a first imaging optical system to be examined are better taken into account.

This object is achieved in a method of the type described above according to claim 1, characterized in that for each pixel values for at least one further, second property of the light is determined and stored in pixels, the series of images is generated by (a) a range of values (b) an image is assigned to each subarea, and (c) the corresponding stored intensity value is assigned to the pixels of each image if the value of the second characteristic associated with the pixel is in the subarea associated with the respective image falls, and otherwise a predetermined intensity value is assigned to them. Then the stored values are processed in an emulation step by converting the series of images into a series of intermediate images, with a constant value of the second characteristic in the emulation for each of the intermediate images received. The constant value of the second property comes from the respective subarea and is different from the values of the second property for the other intermediate images. Subsequently, an emulation image is generated by combining the intermediate images, which emulates an image of the object with the first imaging optics, taking into account the imaging property and the influence of the second property on the imaging behavior.

When generating an image with an optical component to be examined, in addition to the intensity, a further property, for example the color or the polarization effect, is determined for each pixel, for which purpose methods known in the prior art can be used. As well as the intensity, the value of the second property will usually vary depending on the location. The decomposition into individual images, for which the value of the second property, which enters into the evaluation method or the emulation step as a parameter, is constant in each case, makes it possible to compare the error with respect to an evaluation or emulation - as in the prior art corresponds - with a value averaged over the entire image for the second property would have been made to decrease. The more and the narrower parts are created, the lower the error becomes.

The subregions can be selected adjacent to each other, however, for processing and the reference to practice, it is advantageous to choose each other at least partially overlapping subregions, preferably only adjacent subregions overlap. A division into For example, subregions can be done using trigonometric functions - the transmittance of a color filter or polarizer, for example, is described by the square of a sine function.

As the predetermined intensity value, it is preferable to select 0, i. as soon as the value of the second property no longer falls in the partial area assigned to an intermediate image, the intensity value for this intermediate image and the relevant pixel is set to zero. It is expedient if images, intermediate images and the emulation image each have the same size, since the processing is easier. Each image, intermediate image and the emulation image thus preferably have the same number of pixels or pixel rows and columns. Of course, you can also use different sizes, if a corresponding adjustment is made.

There are various possibilities for combining the intermediate images with the emulation image. A particularly simple is to add the intermediate images for each pixel. Another possibility, which is likewise easy to implement, is to form for each pixel the mean value of the intensity values of the intermediate images and thus to generate the emulation image.

In particular, when the subregions overlap one another, it is advantageous to weight the intensity values when assigned to an image of the series. This weighting preferably takes place in such a way that the sum of the intensity values weighted for a pixel when assigned to several Subareas corresponds to the original intensity values of the pixel.

As a second property, various properties of the light to be detected come into question, an important property is, for example, the color. Here, the wavelength and / or the color saturation degree are preferably determined and stored for each pixel. This can be achieved, for example, by independently detecting the colors in each pixel, for example by using a wavelength-selective detector with corresponding upstream optics, which detects separately for each color range - red, green and blue. Another possibility is to produce the series of individual images with the aid of color filters which are introduced into the beam path.

A particularly preferred choice of the second property is the polarization state, which gains influence, for example, in the emulation of high-aperture optics. Since this is not detectable as the intensity directly on a CCD, the polarization degree and / or the direction of polarization must be determined and stored for each pixel by measurement. For spatially resolved determination of the polarization, for example, the Stokes parameters which characterize the polarizing optical element can be determined spatially resolved. This method is for example of HW Berry et al. in Applied Optics 16, 3200 (1977 ). Subsequently, the series of images can be computationally generated based on the stored values.

Another possibility is to generate the series of images by passing the light through a polarizer prior to detection, the subregions being determined by the different positions of the polarizer. In such a polarizer, a natural weighting function is already incorporated, which corresponds essentially to the square of a sine function. The subregions are therefore usually quite large and overlap. A combination of polarizer and computational generation of the images is also possible.

gewichtet, wenn der einem Bildpunkt zugeordnete Polarisationswinkel θ in den Teilbereich fällt, wobei C eine Konstante und ϕ der Polarisationwinkel im Zentrum des entsprechenden Teilbereichs ist. Liegt der einem Bildpunkt zugeordnete Polarisationswinkel außerhalb des Teilbereichs, so wird dementsprechend einem Bildpunkt der vorgegebene Intensitätswert, also beispielsweise Null, zugeordnet. Mit dieser Dreiecksfunktion, deren Steigung durch eine entsprechende Wahl der Konstante beeinflußt werden kann, läßt sich eine Wichtung derart erzielen, daß für jedes Bild die Polarisation als im Wesentlichen homogen angenommen werden kann. Dabei ist die Genauigkeit um so höher, je höher die Anzahl der Teilbereiche gewählt wird, wobei jedoch die Anzahl der Teilbereiche mit der Dauer der Emulation abgestimmt werden muß, da mit steigender Anzahl von Bildern der Emulationsschritt länger dauert. Als guter Kompromiß hat sich beispielsweise eine Wahl von 6, 8 oder 12 Teilbereichen herausgestellt. Grundsätzlich ist die Zahl der Teilbereiche frei wählbar. Um die eben beschriebene Dreiecksfunktion im Auswerteverfahren bzw. Emulationsschritt besser handhabbar zu machen, kann sie außerdem beispielsweise mit einer Glättungsfunktion gefaltet werden, so daß sie mindestens einmal stetig differenzierbar wird.If one constructs the series of images mathematically on the basis of the stored values, then this natural weighting function can likewise be used, but there are still a large number and generally more favorable weighting functions available. In an advantageous embodiment of the method, the intensity values become, for example, a function $$C\cdot \left|\phi -\theta \right|$$

weighted when the polarization angle θ associated with a pixel falls within the subrange, where C is a constant and φ the polarization angle at the center of the corresponding subrange. If the polarization angle associated with a pixel is outside the subarea, then the pixel is given the predetermined intensity value, that is to say zero, for example. With this triangular function, the slope of which can be influenced by an appropriate choice of the constant, a weighting can be achieved such that the polarization can be assumed to be substantially homogeneous for each image. In this case, the higher the number of subareas, the higher the accuracy, but the number of subareas must be matched with the duration of the emulation, since the number of images increases as the emulation step takes longer. As a good compromise, for example, a choice of 6, 8 or 12 sub-areas has been found. Basically, the number of subareas is freely selectable. In order to make the triangular function described in the evaluation method or emulation step easier to handle, it can also be folded, for example, with a smoothing function, so that it becomes continuously differentiable at least once.

wenn der einem Bildpunkt zugeordnete Polarisationswinkel θ in den Teilbereich fällt, wobei C eine Konstante und θ der Polarisationswinkel im Zentrum des entsprechenden Teilbereichs ist. Diese Funktion entspricht bei angepaßter Wahl der Konstanten im wesentlichen einer gerundeten Dreiecksfunktion.Another possibility is to weight the intensity values with the function $$C\cdot {\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="imgf0001.png"\; state="\{\{state\}\}">cos</figure-callout>}}^2\left(\phi -\theta \right).$$

when the polarization angle θ associated with a pixel falls within the subrange, where C is a constant and θ the polarization angle at the center of the corresponding subrange. This function corresponds to an adapted choice of the constants substantially a rounded triangle function.

For the images of the series generated with these functions, the polarization over the image field is approximately constant. The images can then be processed substantially error-free in the evaluation process or in the emulation step, where a location-dependence of the polarization is not taken into account.

In a preferred embodiment of the invention, unpolarized light, which should also include circularly polarized light, is also taken into account. This is achieved by assigning one of the partial regions exclusively the degree of polarization zero and assigning to the image associated with this partial region the intensity values of detected, unpolarized light. The intensity values associated with the zero polarization image may then be split into other images and added to the corresponding intensity values. The division is preferably uniform. Alternatively, this image can also be processed separately, either as a whole or in turn divided into different images.

In a particularly preferred embodiment of the invention, a photolithography scanner is used as the first imaging optics, and emulation imaging optics for emulation of the photolithography scanner are used as the second imaging optics. The photolithography scanner is an imaging optic with a very high numerical aperture, while emulation imaging optics is a low numerical aperture optic. With the invention described above, in this way, for example, in the emulation step, methods for emulating image-optical effects at high numerical apertures, as described in the German patent application 10 2004 033 603.2 are emulated in a spatially resolved manner, although the methods described there do not take into account a location dependency of the polarization.

The invention also relates to a device for examining the imaging behavior of a first imaging optics. In such a device as described above, the object according to claim 17 is achieved by storing in the memory module spatially resolved values for at least one further, second property of the light in pixels and the device generating the series of images by (a ) a range of values of the second property is divided into subregions, (b) an image is assigned to each subarea, and (c) the respective stored intensity value is assigned to the pixels of each image if the value of the second characteristic associated with the pixel is that of the respective one Image associated with the sub-area falls, and otherwise a predetermined intensity value is assigned to them. The apparatus also includes an emulation module, which then converts the series of images into a series of intermediate images, with a constant value of the second characteristic being included in the emulation for each of the intermediate images. The constant value of the second property comes from the respective subarea and is different from the values of the second property for the respective intermediate images. Subsequently, the emulation module generates an emulation image by combining the intermediate images. In this way, the influence of the second property on the imaging behavior in the emulation image can be considered spatially resolved.

Preferably, the predetermined intensity value is zero, which simplifies the evaluation. It is also expedient if the subregions partially overlap, depending on which weighting function the device uses.

Preferably, the device generates a series of images and a series of intermediate images of the same size, since this considerably simplifies the handling and no difficulties arise in the distribution of the intensity values on the images or intermediate images. Of course, it is also possible with appropriate adjustment to use different image sizes. The device preferably adds the intensity values of the intermediate images for each pixel and thus generates the emulation image. This is the simplest method for considering the location dependence of the second variable or its variability over the image field in the emulation image. Alternatively, the device can also form for each pixel the mean value of the intensity values of the intermediate images and in this way generate the emulation image. In this case, the device preferably weights the intensity values in the association with an image of the series, which is particularly advantageous when the subregions overlap and an intensity value can be assigned to a plurality of subregions.

In a preferred embodiment of the device, the second property is the color, wherein the wavelength and / or the color saturation level are stored in the memory module for each pixel. This property can be detected relatively easily with the aid of modern detectors on CCD or CMOS basis, it being possible, for example, to detect for each pixel the color ranges red, green and blue individually on a respective CCD with the aid of corresponding optics.

However, the color is not the only choice for the second property. Also other properties that are not necessarily must be visible immediately, come into question. An important second property, in particular with regard to the emulation of high-aperture imaging optics with low-aperture imaging optics, is the polarization state. Here, the polarization degree and / or polarization direction is stored in the memory module for each pixel. In this case, a polarizer can be provided in the device through which the light is passed before detection. The subregions are determined by different positions of the polarizer. In this way, the series of images can be generated directly. Another possibility is to computationally generate the series of images based on the stored values. Here, the polarization degree and / or direction are stored for each pixel at the beginning. A combination of polarizer and computational evaluation is possible. Preferably, the device also assigns one of the subregions exclusively the degree of polarization zero. The image assigned to this subarea is then assigned the intensity values of detected, unpolarized light.

In a particularly preferred embodiment of the invention, a photolithography scanner is provided in the device as the first imaging optics and an emulation imaging optics for emulation of the photolithography scanner as the second imaging optics. In this way, the emulation imaging optics can be used to emulate the polarization properties of the photolithography scanner with spatial resolution, although the underlying emulation method implemented in the emulation module can not take this local dependency into account.

The invention will be explained in more detail below with reference to an embodiment.

Fig.1

eine beispielhafte Vorrichtung und

Fig.2

den Ablauf des Verfahrens.

In the accompanying drawings shows

Fig.1

an exemplary device and

Fig.2

the procedure of the procedure.

In Fig.1 a device is shown as it can be used to investigate the imaging behavior of a (not shown) first imaging optics. From a light source 1, light is fed into a second imaging optics 2. The second imaging optics 2 focuses the light onto a spatial resolution detector 3 with pixels. The light is detected in the image plane in the pixels. The intensity is detected directly in the pixels. The values for the intensity are stored in a memory module 4 in association with the pixels. In addition, a second property of the light is stored in the memory module 4. This can be for example the color, or else the polarization. In the latter case, for example, a rotatable polarizer 5 which can be inserted into the beam path in front of the detector can be provided. The second imaging optics 2 forms an object 6 on the detector 3. For this purpose, the object 6 is introduced at the appropriate location in the second imaging optics 2, so that an image of the object 6 is generated on the detector 3. The object 6 may be, for example, a simple or non-linear color filter, a polarizer or a diffractive optical element. In the latter case may have the setting of the second Imaging optics are adapted to the imaging properties of the object 6. Finally, object 6 may also be a mask as used in photolithography. The light source 1 in this case is preferably a source which emits only one wavelength. If the second property to be registered is the polarization or not directly visible properties, then further devices are necessary, which are not shown here and serve to detect and determine these properties. The values of these properties are then also stored in association with the pixels in the memory module 4.

The values stored for the intensity and the second property, for example the polarization, are then processed by an emulation module 7. In the emulation module 7, an emulation image is generated, which is displayed on a screen 8. In addition, the image can also be saved or / and printed out.

The generation of the emulation image is in Fig.2 outlined. For each pixel intensity and polarization, ie polarization degree and / or direction are stored. These data form the so-called input image data record. From this input image data set, a series of images is generated. In this case, first the minimum and the maximum of the second property can be determined so as to determine the range of values of this property. This value range is then decomposed into subareas, the unpolarized portion of the intensity in the example being a separate subarea is assigned with the degree of polarization zero. This subregion also contains the intensity values of the circularly polarized portion of the light. Of course, the assignment to a separate sub-area is not mandatory. The unpolarized portion, for example, can also be divided among the other subareas - this corresponds to a uniform distribution among the individual images. The other subareas are divided according to polarization angles in a value range from 0 ° to 180 °. In the present example, the polarization angle φ in the center of the corresponding subarea is specified for each image. The subregions can be selected as overlapping or non-overlapping in coordination with the weighting function to be used. In this example, eight sections are selected. The images are then processed in the emulation step. In this case, an image of the object 6 with the first imaging optics is emulated taking into account the imaging property and the influence of the polarization on the imaging behavior. The unpolarized intensity can be treated separately, but does not have to. A division into the polarized images is possible, for example. If the object 6 is, for example, a mask, an image of this mask can be emulated with a photolithography scanner as the first imaging optics. In the second imaging optics 2 is in this case an emulation imaging optics. The imaging characteristics in which both optics differ are the magnification and the numerical aperture. During the processing in the emulation step, intermediate images are generated for each polarization angle φ, wherein in the emulation step, the polarization for the respective image as was constantly accepted. This is due to technical reasons since the methods available in the prior art for emulating or taking account of the polarization can only take constant polarizations into account. Finally, in the present example, the intermediate images are added pixel-by-pixel to the emulation image. In this way, the location dependency in the polarization can be taken into account in the emulation of a photolithography scanner, although the available emulation method according to the prior art actually does not allow this or leads to larger errors.

LIST OF REFERENCE NUMBERS

1

light source

2

second imaging optics

3

detector

4

memory module

5

polarizer

6

object

7

emulation module

8th

screen

Claims (29)

1. Method for studying the imaging behaviour of first imaging optics, in which an object (6) is imaged by second imaging optics (2) into an image plane and light in the image plane is detected with spatial resolution in pixels, the first and second imaging optics (2) differing in at least one imaging property,

   - values of the intensity as a first property of the light being determined for each pixel and stored in image points, and

   - a series of images being produced,

   - characterised in that

   - values of at least one further second property of the light are determined for each pixel and stored in image points,

   - the series of images is produced by

   a. decomposing a value range of the second property into subranges,

   b. assigning an image to each subrange, and

   c. assigning the corresponding stored intensity value to the image points of each image if the value of the second property, assigned to the image point, falls within the subrange assigned to the respective image, and otherwise assigning a predetermined intensity value to them,

   - the stored values are processed in an emulation step by converting the series of images into a series of intermediate images, the emulation being provided with a constant value of the second property for each of the intermediate images, which is taken from the respective subrange and is different from the values of the second property for the respective other intermediate images, and

   - subsequently, by combination of the intermediate images, an emulation image is produced which emulates imaging of the object (6) by the first imaging optics while taking into account the imaging property and the effect of the second property on the imaging behaviour.
2. Method according to Claim 1, characterised in that the subranges partially overlap.
3. Method according to Claim 1 or 2, characterised in that the predetermined intensity value is zero.
4. Method according to one of the preceding claims, characterised in that both the images and the intermediate images respectively have the same size.
5. Method according to Claim 4, characterised in that the intensity values of the intermediate images are added for each image point, and the emulation image is produced in this way.
6. Method according to Claim 4, characterised in that the average value of the intensity values of the intermediate images is formed for each image point, and the emulation image is produced in this way.
7. Method according to one of the preceding claims, characterised in that the intensity values are weighted for the assignment to an image of the series.
8. Method according to one of the preceding claims, characterised in that the second property is the polarisation state, the degree of polarisation and/or the polarisation direction being stored for each image point.
9. Method according to Claim 8, characterised in that the series of images is produced by sending the light through a polariser (5) before the detection, the subranges being established by different settings of the polariser (5).
10. Method according to Claim 8, characterised in that the series of images is produced computationally with the aid of the stored values.
11. Method according to Claim 10, characterised in that the intensity values are weighted with a function $$C\cdot \left|\varphi -\theta \right|,$$

    

    
    when the polarisation angle θ assigned to an image point falls within the subrange, where C is a constant and θ is the polarisation angle at the centre of the corresponding subrange.
12. Method according to Claim 10, characterised in that the intensity values are weighted with the function $$C\cdot {\cos }^2\left(\mathit{\varphi }-\theta \right),$$

    

    
    when the polarisation angle θ assigned to an image point falls within the subrange, where C is a constant and ϕ is the polarisation angle at the centre of the corresponding subrange.
13. Method according to one of Claims 8 to 12, characterised in that exclusively the degree of polarisation zero is assigned to one of the subranges, and the intensity values of detected unpolarised light are assigned to the image assigned to this subrange.
14. Method according to Claim 13, characterised in that the intensity values assigned to the image with the degree of polarisation zero are distributed between other images and added to the corresponding intensity values, the distribution preferably being carried out uniformly.
15. Method according to one of Claims 1 to 7, characterised in that the second property is the colour, and the wavelength and/or the degree of colour saturation are stored for each image point.
16. Method according to one of the preceding claims, characterised in that a photolithography scanner is used as the first imaging optics and emulation imaging optics for emulating the photolithography scanner are used as the second imaging optics (2).
17. Device for studying the imaging behaviour of first imaging optics, comprising

    - second imaging optics (2), by which an object (6) is imaged into an image plane and which differs from the first imaging optics in at least one imaging property,

    - a spatially resolving detector (3), which has pixels and by which light in the image plane is detected in the pixels,

    - a storage module (4), in which the values of the intensity as a first property of the light are stored with spatial resolution in image points,

    - the device producing a series of images,

    - characterised in that

    - values of at least one further second property of the light are stored with spatial resolution in image points in the storage module (4),

    - the device produces a series of images by

    a. decomposing a value range of the second property into subranges,

    b. assigning an image to each subrange, and

    c. assigning the corresponding stored intensity value to the image points of each image if the value of the second property, assigned to the image point, falls within the subrange assigned to the respective image, and otherwise assigning a predetermined intensity value to them,

    - the device furthermore comprises an emulation module (7) which converts the series of images into a series of intermediate images, the emulation being provided with a constant value of the second property for each of the intermediate images, which is taken from the respective subrange and is different from the values of the second property for the respective other intermediate images, and

    - by combination of the intermediate images, the emulation module (7) produces an emulation image which emulates imaging of the object (6) by the first imaging optics while taking into account the imaging property and the effect of the second property on the imaging behaviour.
18. Device according to Claim 17, characterised in that the subranges partially overlap.
19. Device according to Claim 17 or 18, characterised in that the predetermined intensity value is zero.
20. Device according to one of Claims 17 to 19, characterised in that it produces a series of images and a series of intermediate images respectively of the same size.
21. Device according to one of Claims 17 to 20, characterised in that it adds the intensity values of the intermediate images for each image point, and produces the emulation image in this way.
22. Device according to one of Claims 17 to 20, characterised in that it forms the average value of the intensity values of the intermediate images for each image point, and produces the emulation image in this way.
23. Device according to one of Claims 17 to 22, characterised in that it weights the intensity values for the assignment to an image of the series.
24. Device according to one of Claims 17 to 23, characterised in that the second property is the polarisation state, the degree of polarisation and/or the polarisation direction being stored in the storage module for each image point.
25. Device according to Claim 24, characterised in that a polariser (5) is provided, through which the light is sent before the detection, the subranges being established by different settings of the polariser (5).
26. Device according to Claim 24, characterised in that it produces the images computationally with the aid of the stored values.
27. Device according to one of Claims 24 to 26, characterised in that it assigns exclusively the degree of polarisation zero to one of the subranges, and it assigns the intensity values of detected unpolarised light to the image assigned to this subrange.
28. Device according to one of Claims 17 to 23, characterised in that the second property is the colour, and the wavelength and/or the degree of colour saturation are stored in the storage module (4) for each image point.
29. Device according to one of Claims 17 to 28, characterised in that a photolithography scanner is provided as the first imaging optics and emulation imaging optics for emulating the photolithography scanner are provided as the second imaging optics (2).

Images